Boston , MA —Never before have doctors had so many tests at their disposal to screen for, diagnose, and monitor health problems. When doctors recommend a certain test, patients are bound to have questions. Medical Tests: A Practical Guide to Common Tests , published by Harvard Health Publications, answers the essential questions and more for a variety of common tests.

Readers of Medical Tests can look up common medical tests and learn how to prepare, what to expect during the test, any risks, what to do afterward, how soon to expect the results, and what the results mean. Being armed with information can help patients reduce pre-test anxiety.

The report includes information on the most popular tests, including: angiography; biopsies of the breast, endometrium, lymph node, prostate, and skin; bone density tests and bone scans; colonoscopy; CT scan; echocardiogram; MRI scans; mammogram; Pap smear; allergy scratch tests; sigmoidoscopy; ultrasounds; x-rays; and more.

Below is an example of some of the information on an Electrocardiogram (EKG) test that you'll find in the report. This test diagnoses heart attacks and rhythm abnormalities.

How do I prepare for an EKG?

If you have a hairy chest, a nurse might have to shave several patches so that the suction cups used in the test can hold to your skin.

What happens during the test?

While lying on your back, stickers or small suction cups (called leads) are stuck to your skin across your chest and on each arm and leg. The leads record electrical activity coming from your heart. You must remain still but won't feel anything. However, you should notify the person performing the EKG if you have any chest pain during the procedure. The test takes three or four minutes.

When will I get the results?

If the EKG is performed by your doctor, he or she can interpret the results immediately. However if it's performed by a technician, you will have to wait for your doctor to interpret the results.